It lies entirely within Charlton County.

The highway begins at an intersection with SR 23/SR 121 at a point just north of the Florida state line (and near their southernmost point in the state).

It heads northwest, skirting the nearby Florida state line to its west.

Geographically, it is the second-southernmost state highway in the state, after SR 23/SR 121, which have their southern ends just a little further south than SR 185.

[2] The entire route is in Charlton County.